In the manufacture of electronic products, great value is placed upon cost savings, physical size and weight savings, and electrical performance. Amongst other factors, the cost of an electronic product or subsystem is related to the area of a printed circuit board (“PCB”) or substrate (“printed circuit board”, “PCB”, and “substrate” are used interchangeably throughout this disclosure) upon which components are mounted, whether for electrical connection or mechanical operation. The size and weight of the end product being manufactured are related to the number and size of the one or more PCBs forming the product or subsystem. Electrical performance is related to the length of signal lines between components, the distance between a component and the power source for the component, the distance between the power and ground pads on a component and the noise filtering components to the power and ground inputs, and other factors.
Noise filtering of power and ground (often termed “decoupling”) of an electronic component in the current art requires incremental substrate or PCB area corresponding to each added passive component. In some cases electronic design is sub-optimized by eliminating some passives due to footprint constraints. Cost is increased by the need for a reflow step in module assembly.
In the current art, footprint area is sometimes decreased by using the smallest surface mount devices (“SMD”) possible, using packaging that combines several passives into one package, and making cost/area/performance tradeoffs by eliminating passives that, while they may improve the quality of the electronic design, are not strictly required.
In some constructions, stacked dies (individual integrated circuits stacked one upon the other) are used to minimize footprint area. With stacked dies, wire bonding is typically done independently for each die. That is, each die is wire bonded to the substrate, which can result in long bond wires, aggravating wire wash (bowed wires due to the flow of plastic in injection molding process) and adding inductance. Occasionally, stacked dies are bonded from die to die, requiring both dies to be designed with bond pad placements to accommodate the sister die's needs. Stacked dies are not an option with camera sensor chips, in that the sensor matrix must be exposed to a lens.
Current construction methods require additional footprint area as components external to semiconductor dies are added. Also, it may not be possible, due to mechanical constraints or simply too many components, to place all of them optimally, for example to place filtering components close to power and ground pins. This may diminish noise-reducing effectiveness.
What is needed is a method for connecting components associated with a semiconductor die wherein the components are optimally placed, requiring little or no additional area upon the system printed circuit board or substrate.